A week. According to Leha Health Network, it takes a week for black coffee to lose weight, and the number of times of drinking coffee should be quantified regularly. Do not drink at night, take it before dinner every day, take 1 bag, add appropriate amount of warm water and mix well. Taking canna avocado black coffee before meals can effectively enhance the body's satiety, reduce food intake, and also help promote gastrointestinal metabolism, thus reducing oil.